1. Field of the Invention
The present invention generally relates to seed planting machines for dispensing seeds at a controlled rate into a seed furrow and, in particular, to an improved potato seed planter that is adapted to deposit individual seeds in one or more furrows with precision and at relatively high speed.
2. Description of Related Art
Seed planters of various designs have been used to dispense seeds at a controlled rate. In a typical arrangement, a tractor is coupled to a frame and one or more seed planters are attached to the frame. Each seed planter includes a hopper containing the seeds to be planted and a plow that opens a furrow or crop row in the ground. The seeds are removed from the hopper and dropped into the open furrow at a controlled rate. Conventional seed planters may also include furrow closing discs to cover the seeds with soil and an apparatus that provides fertilizer and/or insecticide as the seeds are planted.
Conventional seed planters also include rotatable wheels that contact the ground and distance monitoring devices for controlling the seed discharge rate so that proper seed spacing is achieved. Conventional seed planters, however, are very difficult to use in conjunction with potato seeds because potato seeds are relatively large, vary widely in size, and have irregular outer surfaces. Further, potato seeds can be easily bruised or damaged, and potato seed is very expensive. In contrast, conventional seed planters are typically used with seeds that have generally the same size and configuration, and the seeds are relatively small and not easily damaged.
Potato seeds are used to grow potatoes in various locations throughout the world, especially in the states of Idaho, Washington and Oregon. Typical potato crops may include hundreds or even thousands of acres, and several different types and kinds of potatoes may be grown in the same field or on the same farm. The potatoes that are grown generally have a different size depending upon the intended end use of the potatoes. For example, if the intended use of potatoes is for french fries, then it is desirable to produce the largest possible potatoes. On the other hand, if the intended use of the potatoes is for fresh produce or baking potatoes, then a smaller size is generally desired.
The dominant factor in determining the size of the potatoes in crop is the spacing of the seeds at the time of planting, unless the crop is impacted by extreme weather or other abnormal conditions. For example, a Russet Burbank potato that is planted with a nine-inch spacing between seeds and rows 36 inches apart will produce potatoes suitable for sale as fresh produce and baking potatoes. On the other hand, spacing of the same potato seed 14 inches apart and in the rows that are 36 inches apart will produce fewer, but much larger potatoes suitable for processing into french fries.
Potatoes are an expensive crop to grow because the potatoes require extensive cultivation and nurturing. Potatoes also require the use of expensive and sophisticated harvesting and handling equipment, which must be carefully designed to prevent bruising or damage to the potatoes. In addition, potato seed is very expensive because it is grown in special disease free regions and under carefully monitored conditions. Seed potatoes are generally smaller than standard production crops and, like standard potato crops, the size of the seed potato is generally determined by the spacing of the potato seeds in the field at the time of planting. Because potato seed is very expensive, it is very desirable to prevent wasting of any of the seed.
In order to decrease cost, seed potatoes are commonly cut into pieces prior to planting because all that is required for a seed is a piece of the seed potato that contains a potato eye. Disadvantageously, because the seed potatoes are cut into various shapes and sizes, potato seeds are not round and they do not have a uniform shape. Consequently, potato seed is very difficult to handle and move in a uniform manner. Thus, for example, when potato seed is loaded into a seed hopper, it does not flow or move well through the hopper. Additionally, potato seed pieces have a tendency to become interlocked or intertwined, which makes the potato seed even more difficult to handle and defeats the purpose of cutting the potato seed into pieces.
Conventional potato seed planters often have difficulties in moving the interlocked seeds and properly planting individual seeds at the desired locations. In particular, conventional potato seed planters often "skip" one or more locations where a potato seed should be planted and the planter frequently places two seeds at the same location (commonly known as a "double"). Each of these problems has significant financial consequences to the farmer because it generally costs the farmer the same amount to grow and harvest a field planted at 85% capacity or at 100% capacity. Thus, each time the planter "skips" a desired location, that directly translates into lost profits for the farmer. On the other hand, a field planted at 105% of its capacity due to "doubles" translates into an increased seed cost and lost profits for the farmer. Disadvantageously, because conventional potato planters often both "skip" and plant "doubles," this can significantly impact the number of potatoes harvested and the cost to the farmer.
Conventional potato seed planters often plant multiple rows simultaneously. For example, a conventional potato planter may plant 4, 6 or 8 rows at the same time. Conventional potato planters also include a mechanism that picks potato seeds out of the seed hopper and then drops the seeds into a furrow being plowed. These conventional potato seed planters are described in more detail below.
One type of conventional potato seed planter includes a number of picks or spikes attached to a wheel that rotates through a seed bowl. The picks impale pieces of potato seed from the seed bowl and a cam mechanism is provided to withdraw the picks from the potato seed as the wheel rotates in order to drop the potato seed into a discharge chute where it then falls to the ground.
Pick-type potato seed planters, however, suffer from significant drawbacks because if a rock enters the seed bowl, the pick cannot pick the rock up and it will "skip" each time the rock is in position to be picked up. These rocks, and other foreign matter, can easily damage or break the picks, and broken or damaged picks require expensive and time-consuming repairs. In addition, if the farmer does not know that a pick has been broken or damaged, or that a rock has entered the seed bowl, that may result in numerous skips that are very difficult, if not impossible, to subsequently correct. The picks may also impale more than one potato seed at a time and that results in a "double" being planted. Additionally, each pick has only one opportunity to impale a potato seed during each rotation of the wheel and if the potato seed is not in position to be impaled by the pick, the planter will "skip." Further, the picks and the mechanism holding the picks must be constantly adjusted and changed depending, for example, upon the type or size of the seed.
Another conventional potato planter includes a number of cups or scoops mounted on a chain or belt in which the potato seed is removed from the seed bowl by the cups or scoops. Disadvantageously, multiple seed pieces are often removed from the seed bowl by a single cup. In order to remove the extra seed pieces, a vibration unit vibrates the belt or cups in hopes of shaking the extra seed pieces out of the cup. The vibration unit, however, often fails to remove the extra seed from the cup, or it may remove all the seed from the cup. In addition, these conventional cup-type potato planters have a relatively slow speed that lowers the yield and requires additional equipment to plant a large crop. This slow speed may be particularly undesirable when the crop has a small planting window or when planting multiple crops. This cup-type conventional planter also requires constant adjustments depending upon, for example, speed of the planter and size of the seed pieces.
Another known potato seed planter includes a rotatable hub with a plurality of outwardly extending arms. A cup is attached to the outer end of each arm and a vacuum is associated with each cup to secure a seed within the cup. Thus, as the cup is rotated through a portion of the seed hopper, the vacuum is used to hold a seed within the cup. At a designated point, the vacuum is eliminated and the seed is released so that it can pass through a chute and into a furrow in the soil. Disadvantageously, the vacuum-type planter also picks up rocks, dirt, debris or other foreign matter that decreases the vacuum pressure or plugs the vacuum tubes. Consequently, the vacuum tubes must be frequently cleaned to remove the debris. Undesirably, the vacuum-type planter also has a tendency to remove the protective coating or otherwise damage the potato seed. The vacuum-type planter also requires extra horsepower and fuel to run the vacuum pump, and it increases the weight and complexity of the potato planter.